How does it work?

[Arbalest]

I've long been fascinated by Aircraft engines, in particular Radial and Rotary types. I was surprised as a young man to see that early types used in WW1 fighters had the crankshaft bolted to the airframe and that the cylinders (with prop attached) rotated around the crank. Later Radials, particularly those used in WW2 aircraft had the bulk of the engine including the cylinders fixed to the airframe and the crankshaft rotated in the more conventional manner.

Hope you're still with me ...

I've recently read that Siemens developed a 160 hp 11 cylinder rotary engine around 1917 in which the crankshaft rotated in one direction at 900 rpm while the crankcase and cylinders rotated in the opposite direction at 900 rpm!

I'm having real trouble visualising exactly how this worked!  Anyone care to explain, preferably in simple terms! 

[mklotz]

Wikipedia has a picture of it...

http://en.wikipedia.org/wiki/Siemens-Halske_Sh.III

but not much technical detail.

[tvoght]

US Patent # 1084192 is quite possibly the patent for the engine that Marv has shown. Patents can be a pain to read, but there seem to be some fairly clear illustrations. From the patent (by Ernst Becker and Franz Dinslage, and assigned to Siemens and Halske):

"Our improved engine is an internal combustion engine comprising one or more intermediate gears between the cylinders and the crank-shaft located in the center of the engine arrangement."

Find the Google Patents page (which is mysteriously harder to find than it should be) and from there search for 1084192.

--Tim

[AussieJimG]

In 1906, Charles Redrup demonstrated a two cylinder to the Royal Balloon Factory at Farnborough in which the cylinders rotated in one direction and the crankshaft in the opposite direction. He developed this "reactionless" engine up to 150HP for aircraft use and also built 3 cylinder engines for both aircraft and motorcycles.

Source: Bill Fairney: The Knife and Fork Man - The life and Work of Charles Benjamin Redrup, Diesel Publishing, UK. An interesting book about an interesting man. It is available from Camden Publishing in UK.

Jim

[BillTodd]

An interesting book about an interesting man. It is available from Camden Publishing in UK.

Yes it is and it gets a second recommendation from me   - I particularly liked his swash plate motors

There is a photo of the Redrup 'reactionless' engine.

It looks to me like it used a bevel geared differential (like the Siemens engine) at the rear of the engine :

i.e. the engine crank-casing has one bevelled pinion (with a bearing into the fixed casing)  through which, passes the crank-shaft to the second, rear,  pinion with the crank-shaft bearing to the fixed casing.

The two pinions are flanked by bevel gears running on shafts fixed to  the fixed-casing.

The prop mounts to the front of the crank case (thus running at half engine speed)

Bill